I'm putting a south bend clutch in, while i was at it i installed a new crank seal, would it be ok to run the engine witht just the flywheel and no clutch/trans? i want to set the high idle for a while to see if the seal leaks before i assemble everything just to be safe. would it throw the engine off balance or anything? should i support the back of the motor?

 

without very securely attaching that 930 or so # motor to the frame, I wouldnt do it. when she fires off, she'll torque over and when shutting down. i dont recommend it.

it will not affect balance of the motor, you just dont have 33% of the engine support in the truck.

 

would there be anything that would get streached too tight or anything becuase of the engine moving around? Just hate to ruin a 900 dollar clutch in a hundred miles because of a defective seal.

 

Do not start your engine without the trans and all supports to hold it in place. These things rock around pretty good when shut down. I would be worried about the engine beating aginst one of the fenders or other parts in the engine bay.

 

The engine is not going to beat around the fenders.
It may rock back and forth because of the mid-engine mounted engine mounts. I would set up jack stands at the front and rear of the engine and let it rip. As for clearences, the fan and shroud would be my biggest concern.

Anytime I replace a rear crank seal, I always run the engine and drop the flywheel back down to check the deal.

 

i have never heard of running an engine to check a new rear seal...i have re built hunderds of engines ,never had one leak while under warranty

 

While good technicians rarely screw up crank seals, I have had to replace seals for a lot of young inexperienced techs. It has been standard operating procedure to run engines with no tranny in several shop I have worked at. Let the engine run for 15 - 20 minutes, grab a cup of coffee, whatever.
This is a lot easier than having to deal with an angry customer, or pulling the transmission back out later on.

 

I have bought brand new bad parts. Just because it is new doesn't gurantee it is not defective.

 

of course i realize things can change with time, i retired from automotive repair in 1986 but like i said, i never heard of it

 

It's not if i installed it right but being i purchased the seal at kragen makes me worry, it's a felpro seal, are those good seals? But if by some chance it's defective, then goes a weekend on pulling the tranny out, and 900 bucks because of an oil contaminated clutch disk. So nobody's ran there dodge with no trans?